[RFC] Create schemas/models to model the backend data

Overview

Firestore is a NoSQL database, which allows developers to be flexible and add new features instantly, however error handling and handling various edge cases to data becomes difficult.

Proposed Solution

Create model classes and initialize them whenever we fetch the data from DB. Instead of sending the raw object we get from firestore, we initialize the data we get using a class, that class will abstract all the logic related to data, and our service that we use to fetch the data currently will return the instance of that class

This way we will be able provide null values to fields we don't get and the user (developer who will be using the service function) won't have to check for undefined fields on their end.

Since most of the error handling logic and other data manipulation logic will be handled, this will save us a lots of repetitive code.

No files, tests, or specific entry points are named. Start by tracing the existing services that fetch raw objects from Firestore and their consumers; the work is done when model instances are returned, missing fields have defined null values, and data handling is centralized as proposed.